An air conditioning system providing cooling and dehumidification of a room is known in the art as disclosed in WO03/029728 pamphlet. The air conditioning system includes a refrigerant circuit provided with a heat-source side outdoor heat exchanger and a utilization side indoor heat exchanger and runs a refrigeration cycle by circulating refrigerant through the refrigerant circuit. Further, the air conditioning system dehumidifies the room by setting the refrigerant evaporation temperature in the indoor heat exchanger below the dew point of the room air and condensing moisture in the room air.
A dehumidifier is also known which includes heat exchangers each provided with an adsorbent on the surface thereof, as disclosed in Japanese Unexamined Patent Publication No. H07-265649. The dehumidifier includes two heat exchangers and operates so that one of the two heat exchangers dehumidifies air and the other is regenerated. During the operation, the heat exchanger adsorbing moisture is supplied with water cooled by a cooling tower while the heat exchanger being regenerated is supplied with warm discharged water. Further, the dehumidifier supplies the air dehumidified by the above operation into the room.
—Problems to be Solved—
As described above, the air conditioning system disclosed in WO03/029728 pamphlet copes with indoor latent heat load by setting the refrigerant evaporation temperature in the indoor heat exchanger below the dew point of the room air and condensing moisture in the air. In other words, although indoor sensible heat load can be coped with even if the refrigerant evaporation temperature in the indoor heat exchanger is higher than the dew point of the room air, the refrigerant evaporation temperature is set at the lower value in order to cope with the latent heat load. This provides a large difference between high and low pressures in the refrigeration cycle and raises the input to the compressor, which leads to a problem that only a small COP (Coefficient Of Performance) can be attained.
On the other hand, the dehumidifier disclosed in Japanese Unexamined Patent Publication No. H07-265649 supplies water cooled by the cooling tower, i.e., cooled water having not much lower temperature than the room temperature, to the heat exchanger. Therefore, the dehumidifier has a problem that it can cope with indoor latent heat load but cannot cope with indoor sensible heat load.
The present invention has been made in view of the foregoing points and, therefore, its object is to provide an air conditioning system which can cope with both of indoor sensible heat load and latent heat load and attain a high COP.